Cleaning screen



June 12, 1962 L. H. SMITH 3,038,212

' CLEANING SCREEN Filed Sept. 10, 1959 IN V EN TOR.

LOF TON H. SMITH 3,038,212 CLEANING SCREEN Lofton H. Smith, 2164 Collins Drive NW., Atlanta 18, Ga. Filed Sept. 10, 1959, Ser. No. 839,152 2 Claims. (Cl. 19-95) This invention relates generally to the art of cleaning fibers and more particularly to an improved type of cleaning screen, which is particularly suited for the cleaning of cotton stock.

Previously in this art many diiferent types of cleaning screens have been provided, such as the widely known type of adjustable grid bars now in great use throughout this country, or a thin, perforated, undulated screen. The thin screen is extremely weak and cannot take the constant battering to which this type of cleaning screen is constantly subjected. Furthermore, the openings formed therein are circular and therefore are not large enough for a sufficient amount of trash to be expelled. The openings cannot be made too large since this will result in the passage of a great quantity of cotton fiber through the openings along with the trash. Even further, a number of pockets are formed in the undulated areas in which collections of dirt may be deposited, which will not fall through the perforations but will be picked up by cotton stock subsequently passing the area and thus the efficiency of the cleaning operation is greatly diminished.

Other types of cleaning screens contemplated is the use of an expanded metal screen or a metallic plate having elongated slots which slots are formed through portions of the plate with the planes of the slots being at an angle to the axis of the plate, all of which form the same angle with the axis and are connected by vertical walls. The metal screen is formed from the usual type of expanded metal and for this reason this screen is week since the openings are extremely large with respect to the size of the walls therebetween. Furthermore, some of the fibers will project down into the openings and will be pulled across the sharp edges of the screen which are Very likely to damage the fibers and even cut off the projecting portions thereof. A great disadvantage is present in that the fibers wrap about the relatively small walls between the respective openings, and thus cause the walls between the openings to be lapped with fibers, thereby greatly diminishing the cleaning efliciency. As for the metal plate having the elongated slots, this arrangement has been found to allow large collections of dirt to be deposited between the vertical walls and the inclined walls in which the slots are formed. Furthermore, since the walls were inclined in the direction of travel of the cotton, there were no projections against which the cotton would be battered in order to loosen and remove the dirt and trash within the cotton, and accordingly this type of screen removes little of the trash contained within the cotton which is to be cleaned.

With all of the previous types of screens used, any of the dirt which is collected is thrown back into the moving cotton stock by drafts which are created by the quickly rotating beaters or cylinders. The grid bar arrangement is expensive and has many movable and adjustable parts. However it is the best that the prior art could offer.

With these defects of the prior art in mind, it is the primary object of this invention to provide a cotton stock cleaning screen which will very efficiently remove a great deal of the trash and dirt contained in the stock.

Another object of this invention is to provide a device of the character described wherein the formation of deposits of dirt and trash along the screen is prevented.

A further object of this invention is to eliminate the wrapping of cotton fibers about the walls between openings within this screen so that there may be smooth and ited States Patent 3,638,2l2 Patented June 12, 1962 uninterrupted passage of the stock through the device except for the periodic battering of the stock against projecting portions of the screen.

A still further object of this invention is to provide a simple and inexpensive device and yet one which is exceedingly efiective for the purposes for which it is designed.

The foregoing objects and others ancillary thereto are accomplished according to a preferred embodiment of the invention, wherein a curved metal plate is formed with a plurality of elongated openings formed in rows, with the openings in adjacent rows being offset from each other so as to assure that the full width of the device provides openings for trash. The major axes of the elongated openings are disposed transverse to the direction of travel of the cotton stock so that relatively short distances are open in the direction of stock travel to prevent the longer fibers, creating the bulk of the cotton stock, from falling through the cleaning screen while the openings are sufficiently large to properly dispose of the trash. Furthermore, the leading edges of the openings are lowered and the trailing edges raised, so that the trash falling and being forced therethrough will be directed by these raised and lowered edges downwardly into the dirt collection chamber and cannot be tossed back into the moving cotton stock. Furthermore, the raised portions provide surfaces against which the stock may periodically be battered so as to shake the trash loose from the stock. The closest distances between adjacent openings is large enough to prevent the fibers from wrapping around the walls, and a large portion of the walls between openings is disposed in a substantially flat plane, that is, fiat with respect to the axis of the screen so that no dirt collection pockets may be formed thereon.

The novel features that are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment when read in connection with the accompanyings drawings, wherein like reference characters indicate like parts throughout the several figures and in which:

FIG. 1 is a vertical sectional view taken through a typical type of down stroke beater which is used in the opening and cleaning processing of cotton stock and the like;

FIG. 2 is an enlarged fragmentary view of a portion of the cleaning screen of FIG. 1 enlarged to illustrate the arrangement thereof;

FIG. 3 is a plan view of a portion of the fiber cleaning screen;

FIG. 4 is a vertical sectional view taken substantially along the plane defined by reference line 44!- of FIG. 3 illustrating details of construction thereof, and

FIG. 5 is a vertical sectional view taken along the plane defined by reference line 5-5 of FIG. 3 illustrating the raised and lowered edges surrounding the slots proper.

Referring now more particularly to the drawings, M designates a typical type of machine in which the cleaning screen is to be used, with B designating a typical type of down stroke beater. The lower portion of machine M has a chamber D which is the dirt collection chamber and in which the dirt deposited through the screen will be collected. It should be noted that the entire lower portion of the machine casing is formed by the screen S, with the leading portion of the casing being formed by a metal plate 10 joined to the leading portion of the screen S, and the delivery portion of the machine having a plate 12 which is connected to the trailing portions of screen S.

The delivery 14, may be in the form of a hopper through which cotton stock is fed into the device, and a delivery chute 16 is provided to discharge the stock from the machine.

The screen proper is formed by a metal plate 18 having a plurality of elongated openings 20 formed therethrough, which openings are formed in a row across the screen, so that the major axis of the openings will be disposed transverse to the intended path of travel of the cotton stock. Disposed on either side of the rows of openings 20, are similar rows of identical openings 21, which are offset from openings 20, so that the entire width of the screen is provided with open areas in which the trash may be deposited. It is to be here noted that in order to prevent the entanglement of fibers about the walls between adjacent openings, the walls between the openings, for instance the distance between points X and Y shown by a dotted line in the lower portion of FIG. 3, should be about one-half inch which will be between onefourth and one-half the staple length of the fiber to be processed which ranges from about one inch to about two inches, so that it will be very difficult if not impossible for the fibers to get entangled about these walls, while still providing ample open areas for trash removal.

The leading edges of the openings are bent downwardly as indicated at 22, and the rearward edges are bent upwardly as indicated at 24, so that, as more clearly illustrated in FIG. 5, the portions 22 and 24 form guide walls for directing the trash downwardly into the dust collection chamber D in such a manner that the dirt is thrown beneath a flat wall portion 26 of the plate 18 so that the returning of trash to the area of the cotton stock is prevented.

The flat walls 26 which are disposed between adjacent openings and which constitute the major portion of the walls between the openings, serve to not only keep the trash from returning to the beater chamber, but also aid the cotton in moving expeditiously through the machine, so that the cotton moves quickly and smoothly through the device except for the periodic turbulence of the cotton caused by the raised edges 24 in the trailing portions of the slots.

It may thus be seen that the cotton stock flowing through the inlet 14 will slide down along plate and then be carried by the beater B across the screen section S which constitutes a large portion of the area over which the stock is to be carried. The stock is then thrown by centrifugal force and by air drafts up along plate 12 and is discharged through delivery chute 16. All during this time, the cotton stock is being hammered against the upraised edges 24 so as to jar loose the trash within the stock, and the fibers are prevented from being wrapped about the walls between slots and the trash is prevented from returning to the stock, all in the manner which is explained above.

It should now be clear that a new and improved fiber cleaning screen for cotton stock has been provided which is extremely simple, yet the simplicity of the device does not detract from its performing these novel functions which could not be performed by the structures in the prior art.

Although a certain specific embodiment of the invention has been shown and described, it is obvious that many modifications thereof are possible. The invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

That which is claimed as new is:

1. In a machine for cleaning fibers, a screen formed in a curved surface about an axis and having an arc of less than a plurality of elongated openings in said screen formed in rows, the major axes of said openings being disposed parallel to said axis, the openings of each row being spaced apart a distance approximately equal to the width of each opening, means for moving fiber stock in a path along said screen in a direction transverse to said axis and transverse to the major axes of said openings, the upstream elongated edges of said openings being depressed slightly below the arc of curvature of the screen and into the openings, the downstream elongated edges of the openings being slightly raised above the arc of curvature of the screen, the remainder of the screen other than said edges of the openings lying in said arc of curvature, and the shortest distance between openings in adjacent rows being between one-fourth and onehalf the staple length of the fiber to be processed.

2. A machine for cleaning fibers according to claim 1, wherein the said elongated openings of adjacent rows are offset longitudinally with respect to each other.

References Cited in the file of this patent UNITED STATES PATENTS 1,681,555 Onge Aug. 21, 1928 1,917,896 Mitchell July 11, 1933 1,935,745 MacKenzie Nov. 21, 1933 FOREIGN PATENTS 2,995 Great Britain of 1869 

